1. Field of the Invention
The present invention relates to gas emission sample containers for collecting gas emissions from motor vehicles and, more specifically, to fittings for use in gas emission sample containers.
2. State of the Art
Expandable, sealed containers or bags are employed for collecting and temporarily storing gas emissions from motor vehicles before the collected emissions are analyzed by suitable test equipment. Such containers are expandable to a predetermined volume to collect a known quantity of gaseous emissions.
Typically, a plurality of such containers, such as six containers, are connected through suitable conduits, valves, etc., to a test apparatus to collect separate quantities of gas emissions from a vehicle and from ambient atmosphere. The emission samples from a motor vehicle under test are collected in the sealed containers as the motor vehicle is operated according to a prescribed test schedule corresponding to various engine operating conditions.
The expandable containers include a fitting sealingly mounted in each container which is connected to the test apparatus to receive gas emissions from the vehicle under test. The fitting directs the gas emissions into the container for storage, as well as enabling the stored gas contents to be evacuated from the container for subsequent analysis. The fitting and the sealed container are made of a chemically inert material, such as a fluorinated carbon plastic, i.e., plastics sold under the registered trademarks TEFLON, KYNAR, and/or TEDLAR.
Accurate testing of gasses in a gas emission sample container requires the complete inflation of the container to a constant volume without internal dead spots as well as the complete evacuation of all gasses from the container. Specially designed, small, smooth fittings have been employed in gas emission sample containers to prevent the formation of internal dead spots during the evacuation of gas from such containers. In addition, hollow conduits or tubes having spaced apertures formed therein have been mounted within such containers and connected to the fitting to ensure complete and even inflation and evacuation of gas to and from the container, without stratification of the gas within the container.
However, previously devised fittings for gas emission sample containers have required a special design to minimize space within the container and to provide a smooth exterior shape to prevent the formation of dead spots during evacuation of gas from the container. As shown in U.S. Pat. No. 5,074,155, such fittings have also been designed with internal bores connected in fluid flow communication with a port extending through the fitting. Such designs have resulted in a high cost fitting due to their special construction and the requirement for a small, smooth shape.
Thus, it would be desirable to provide further improvements to fittings employed in gas emission sample containers. It would also be desirable to provide a fitting for a gas emission sample container which minimizes the volume consumed by the fitting within the interior of the gas emission sample container.